The present invention is directed to an artifical denture and more specifically to the means for anchoring the artificial denture between two existing teeth.
It is old and well known in the artificial denture art to permanently secure a bridge in two opposed grooves in spaced apart existing teeth and to secure the artificial tooth or teeth to the bridge in a permanent or detachable manner. The grooves which must be cut in the natural teeth for anchoring the bridge therein are of a considerable magnitude and frequently have to be undercut in order to provide a complimentary interfitting engagement with enlarged projections on the opposite ends of the bridge. While the posterior teeth are usually of a sufficient size to permit the grinding of such large grooves, these methods are generally unsuitable for anterior teeth which are relatively thin.
Other artificial denture devices rely on anchoring a protruding post or bracket into spaced apart existing natural teeth and detachably or permanently securing the bridge to the protruding post or bracket. Once again, it is usually possible to anchor such a post or bracket in the relatively large posterior teeth but extremely difficult if not impossible to anchor such a post or bracket to the anterior teeth. While the use of telescopically adjustable bridge support elements is old and well known in the art, the telescopic adjustment must generally take place prior to the insertion of the bridge support device into the complimentary grooves in the spaced apart existing teeth. Thus, it is extremely difficult to obtain and maintain the proper telescopic relationship prior to the insertion of the device and during the subsequent removal of the bridge for fitting the facings on the bridge prior to the permanent anchoring of the bridge in the existing teeth.
The U.S. Patent to Plotnick No. 2,835,034 discloses a removable denture having a housing secured to a base or saddle adapted to rest on the gum. An artificial tooth or crown is arranged to fit over the housing and is secured to a vertically movable plunger mounted for sliding movement in the housing. The base member is designed to protrude under the overhanging portion of an adjacent tooth on one side and to prevent the vertical movement of the artificial tooth a laterally extending plunger is slidably located in the housing for movement into engagement with the undercut portion of an adjacent tooth on the opposite side. The two plungers are provided with beveled edges which bear against each other within the housing so that as the artificial tooth or crown is moved downwardly over the housing 16, the laterally movable plunger will be cammed outwardly by the vertically moving plunger into engagement with the adjacent tooth, thereby preventing vertical movement of the entire artificial tooth assembly. The cam surfaces on the ends of the plunger disengage when the artificial tooth or crown is moved into final position on the housing thereby eliminating any camming action between the plungers during normal use.
Applicant's own U.S. Pat. No. 4,163,318 is directed to a device for replacing missing teeth in human dentition. The device which is adapted to be secured between two existing teeth is suitable for supporting an artificial denture to replace an anterior tooth or a posterior tooth. The device is comprised of a backing member having a pair of parallel extendable arms slidably disposed in grooves in said backing member on opposite sides of a pinion rotatably mounted in said backing member in simultaneous meshing engagement with teeth on both arms for simultaneously extending both arms in opposite directions upon rotation of said pinion in one direction. The extended ends of each arm is adapted to be disposed in a precut groove in an existing tooth to support the device between two existing teeth. Suitable projections are provided on the surface of the backing member for cooperation with complimentary grooves in the artificial facing. The facing is secured to the backing and the extended arms are secured in the grooves of adjacent teeth by a suitable cement or filling material.